Tape record yourself improvising over the chord progression.
Listen to the tape and critique your rhythm.
Is your tempo steady or do you rush or drag certai passages?
Is your time as solid in the difficult keys as it is in the easy keys?
If not, devote ourself to resolving any technical issues that maybe hindering your rhythm.
Make sure to pay attention to what the rhythm section is doing.
Don’t get absorbed in thinking about what you are going to play. Need a quiet mind.
The rhythm is more important than notes.